Steam or gas turbine



Oct. 8, 1929. K, RDER 1,730,746

STEAM OR GAS TURBINE Filed nec. 29 1927 nnH n' nnnn, or innovar., Gramm? STEAM on Gas TUBBINE Application led December'29,'1927, Serial No.12'48,394, and in Germany `Jam'xary y"7, 1927.

y l My invention relates to an improvement in steam or ga turbines.

vIt is alrea y known to provide steam or l gas turbines having' preponderating axial admission with two rotors rotating in opposite' directions. The blade rims rotating in o posite directions are then mounted withm the space formed between the outer and the inner rotor, both rotors overhanging their bearings. l

The mounting-of the -rows of blades inthe outer rotor of this turbine presents considerable diiiieulties, if it is desired to obtain` a substantial construction, in which a.I loosening of the blades by forces set up by mechanical causes is effectively eliminated. A further requirement of such a turbine is that it should be possible to take it apart as quickly as possible when the machine has been stopped, in

order to render the blades freely/accessible.

'I attain this result by fitting a bushing,

tapered at the outside and split in' an axial plane, or in a number of planes, into the correspondingly bored outer rotor and clamping '-25 it in position by a locking ring, said bushing carrying the rows of blades f the outer rotor. In a modification I employ `a double-taper, the shorter portion then being located in an additional ring, while a locking ring provided with right-hand and left-hand `thread effects the connection with the shaft end. -By tightening the locking ring the, split bushing is rigidly connected with the hollow shaft. The

force holding the parts together is not dimin-l ished in service, since centrifugal forces as well as stresses set up by the heating p rogressing from the insidetowards the outside have not the tendency toloosen the connection, but rather tio tighten it.

In the drawing aflixed heretoA and forming part of myv specification two embodiments of my invention are illustrated'by Way of example. U y

' -The drawings represent in Fig. 1, a longitudinal central section through a part of my improved turbine', in which the bushing is secured within the outer hollow rotor by means of 4.a single locking ung i Fig. 2, a similar section in which a doubletaper bushing is-securedv within the outer rotor by means of two locking-rings and in Figure 3 a transverse section-through Fig ure 1 on the line 3-.3 in that ligure, ring g being removed, and only a few of. the turbine blades or buckets being shown.

reference inthe figures of the drawing.

Referring to Fig. 1 of the drawing, a is the innerrotor, the blades c of which are mounted directly in slots of the rotor body.

Like parts are indicated by like letters of The driving medium is admitted into the turbine by the central bore la of the outer vrotor b. The blades d of this rotor are 'cars a ried by a bushing e. .This bushing is split in A at least one central axial plane, so Vthat it comprises two` or more component parts as may e s een from Figure 3. The portions of the bushing e are fixed within the tapering bore of theouter rotor b by means of an external taper. The assembly. takes place in such a manner that the parts of the bushing provided with the blades are first placed around the bladed inner rotor au The -end of the rotor shaft b is `then pushed over' the taper a of the portions of the bushing in an axial direction.l The drum-shaped rotor b then envelops the tapering bushing. The assembly is now completed by screwing the locking ring-g on to thel end of the outer rotor vZ1 by'v means of the thread h. This locking ring g of the steam on the blades to the rotor b; The

valso serves vfor transmitting the axial thrust I locking ring g surrounds the peripheral portions of the ends of the bushing elements e with a certain amount of clearance. Y'The ends of the bushing elementsare themselves provided with thread i upon which after the' "removal of the lock ring g a correspondingly threaded tool may be placed by means of which the parts of the bushing e may be withdrawn from the shaft b when the turbine 1s to be dismantled.` l j.

Referring to Fig. 2 of the drawing, it w1ll be seen that the embodiment illustrated here differs from that shown in Fig.` 1 only -in so far as the bushing elements e are provided valso on their peripheral portions,- which protrude beyond rotor b, with a taper, on which latter is disposed atapered rlng f. The assembly is effected in the same manner as described with reference to Fig. 1. The locking ring g is in this case provided with an internal left-hand thread h1, h2 by which the correspondingly threaded ends of rotor b and ring f are drawn together, so that thereby the split bushing b is forced into the rotor. By turning the ring g in the opposite direction and by a few light blows with a mallet the connection may easily be loosened and the bushing e be withdrawn to make the blading accessible.

Various modifications and changes may be made without departing from the spirit and the scope of the invention, and I desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art.

I claim as my invention 1. In a steam turbine, in combination, an inner rotor having a plurality of axially spaced circumferential rows of blades on its outer periphery, an outer hollow rotor having similarly spaced rows of blades on its.

inner periphery, both of said rotors overhanging their bearings, said outer rotor having an inwardly tapering bore enveloping said inner rotor along its bladed portion, an externally tapered axially split bushing fitting said bore and carrying said outer rotor blades on its inner periphery, and means adapted to hold said bushing attached to said outer rotor.

2. In a steam turbine, in combination, an inner rotor having a plurality of axially spaced circumferential rows of blades on its outer periphery, an outer hollow rotor having similarly spaced' rows of blades on its inner periphery, both of sai-d rotors overhanging their bearings, said outer rotor having an inwardly tapering bore enveloping said inner rotor along its bladed portion, an externally tapered axially splitl bushing fitting said bore, and carrying said'outer rotor blades on its inner periphery, and a` locking ring adapted to secure said tapering bushing within the bore of said outer rotor.

3. In a steam turbine, in combination, an inner rotor having a plurality of axially spaced circumferential rows of blades on its outer periphery, anouter hollow rotor having similarly spaced rows of blades on its inner periphery, both of said rotors overhanging their bearings, said outer rotor having an inwardly tapering bore enveloping said inner rotor along its bladed portion, an externally double-tapered axially split bushing fitting said bore and carrying said outer rotor blades on its inner periphery, a holding ring having a bore itting the outer taper of v said bushing, and a locking ring disposed between said hollow rotor and said holding ring and having an internal right-hand and left-hand thread adapted to join the correspond'ingly threaded ends of said outer rotor and said holding ring to draw the bushing into said hollow rotor.

4. A steam turbine composed of an integral outer element and an inner element, carrying a plurality of axially spaced circumferential rows of blades on its outer periphery, said outerkelement containing a cone shaped bushing carrying a plurality of axially spaced-circumferential blade rows on KARL RDER. 

